When inspecting the removed NTN bearing during the regular maintenance and operation of Periodic Maintenance NTN bearing equipment and the replacement of peripheral parts, it is necessary to judge whether the secondary NTN bearing parts can be reused and record the good or bad use.
It is also necessary to carefully investigate and record the Periodic Maintenance removed NTN bearings and appearance. In order to find out and investigate the remaining amount of lubricant, the NTN bearing should be well cleaned after sampling.
Secondly, check the raceway Periodic Maintenance surface, rolling surface and mating surface of NTN bearing and the wear state of cage for damage and abnormalities, especially observe the running track of raceway surface.
To judge whether the NTN bearing can be reused, it should be Periodic Maintenance decided after considering the damage degree of NTN bearing, machine performance, importance, operating conditions, inspection cycle, etc.
According to the inspection Periodic Maintenance results, if NTN bearing is found to be damaged or abnormal, please find out the causes and formulate countermeasures according to the damage of NTN bearing.
In addition, according to the Periodic Maintenance inspection results, if there are the following defects, the NTN bearing can no longer be used and needs to be replaced with a new NTN bearing.
a. Any one of the inner and outer rings, rolling elements and cage has cracks and fragments.
b. Any one of the inner and outer rings and rolling elements has peeling.
c. The raceway surface, retaining edge and rolling element are significantly jammed.
d. The cage is seriously worn or the rivets are seriously loosened.
e. The raceway surface and rolling element are rusty and scarred.
f. There are significant indentation and indentation on the rolling surface and rolling element.
g. There is creep on the inner diameter surface of the inner ring or the outer diameter of the outer ring.
h. Overheating and discoloration.
i. The sealing ring and dust cover of grease sealed NTN bearing are damaged seriously.
Proper lubrication and maintenance can give full play to the high service life of Koyo bearings.
1. Grease lubrication
The relubrication of Koyo bearings is carried out during the planned equipment shutdown and Periodic Maintenance supplemented regularly. At the same time, the old grease is removed or squeezed out through the oil drain air.
Wipe the grease nipple clean Periodic Maintenance before adding fresh grease. If the Koyo bearing housing does not have an oil filler, open the Koyo bearing housing cover or end cover to take out the old grease. After cleaning, add fresh grease of the same model.
2. Lubricating oil lubrication
Regularly check the oil level and quality of lubricating oil. Generally, the normal oil level should be Periodic Maintenance within 1 / 3-2 / 3 of the equipment oil level window or mark.
The oil replenishment mode is the oil cup, and the displayed oil level only represents the oil replenishment capacity, while the oil level of Koyo bearing box meets the operation requirements. If the oil level in the oil cup is lower than 1 / 4 of its total volume, oil replenishment can be considered.
Check and replenish oil methods. Take a small amount of lubricating oil as a sample and compare it with fresh lubricating oil. Competent units can consider oil quality test to ensure that the oil quality is qualified.
If the sample looks like a cloud, it may be the result of mixing with water, which is often called oil emulsification. At this time, the lubricating oil should be replaced. If the sample becomes darker or thicker, it may indicate that the lubricating oil has begun to carbonize,
and the old lubricating oil should be completely replaced. If possible, flush the oil circuit with fresh lubricating oil. When replacing the lubricating oil, ensure that the new and old models of the replaced lubricating oil are the same, and supplement it to meet the required oil level.
Use the oil bath lubrication system. If the oil temperature is below 60 ℃ (140 ° f) and the lubricating oil is not polluted, replace the lubricating oil once a year. If the oil temperature is 60-100 ℃ (140-210 ° f), the lubricating oil needs to be changed four times a year.
If the oil temperature is 100-120 ° C (210-250 ° f), the lubricating oil needs to be changed once a month. If the oil temperature is above 120 ℃ (250 ° f), the lubricating oil needs to be changed once a week.
Proper installation and maintenance is an important factor for the normal operation of Koyo bearings. At the same time, attention must be paid to maintaining the cleanliness of Koyo bearings. Koyo bearings must be protected from pollutants and moisture, and must be correctly installed and lubricated.
In addition, the design of Koyo bearing arrangement, the condition of oil seal, the form and replacement cycle of lubricant and special maintenance also play an important role, which must be paid attention to.